Selfmade video transmission between 2 mobile devices
The first tests for video transmission an o UAV was made with Skype ™ which has some drawbacks. Therefore the software has been extended to also transmit video from the Android ™ smartphone to a laptop. Technically this is realized through the preview function on the Android API. Currently 15 frames per second are used. Every frame is converted to a jpeg picture and send as UDP package to the ground station software. This approach has several advantages:
- Frame rate and video quality can be chooses
- Only one app to have UAV control, telemetry data and video downlink
- Video can be mirrored in software if it’s necessary to attach a mirror in front of the smartphone cam.
- Video can be turned
- Should be possible to take pictures or record movies in HD at the same time the preview is transferred.
In the video you see 3 setups. On the first one the WLAN access on the DSL router was used for both, the smartphone and the laptop. The latency was about 0.2 seconds.
On the second one the mobile access (vodafone ™) on the smartphone was used while the laptop still used the WLAN DSL access. This time the latency was about 0.26 seconds. The next mobile tower is only 150 meters away. At this video there a some errors in the pictures which is a bug in the software and has to be fixed.
On the third time both devices used two separate mobile access (vodafone ™) and the latency was about 0.36 seconds which is not too bad for a 3G connection. Especially because of this scenario has to use a kind of “proxy” server for the connection between the two devices.